Diffusion leakage model study on chemical materials taking Liquid Ammonia as an example

It is important to select the correct diffusion model to predict the leakage concentrate of hazardous materials according to their molecular weight properties. Generally speaking, the Gauss diffusion model is usually used for predict light gas diffusion and SLAB model for weight gas. However diffusion model selection is also determined by storage condition, which can greatly change the physical condition and influence predictive model selection. In paper, we took liquid ammonia as an example. Ammonia is gaseous in normal temperature and pressure, and usually be converted into liquid by high pressure storage condition in practice. The gauss model and LSAB model were used in this paper to compare the difference of diffusion process. The result is as follows. For one thing, the spatial dimension predicted by Gauss model was greatly less than that of SLAB model accompanied by much wide spatial range in horizon direction to the predominant wind direction. For another, referencing to AEGL-1 standard, the longest diffusion distance in 4650s by SLAB model is about 6132 meters and the result predicted by Gauss model is about 2880 meters. The difference of influence spatial scope and diffusion distance predicted by two models is 44.7% and 77.2%. So it should be cautious when selecting diffusion model to predict the hazardous material leakage.